Field of the Invention
The present invention relates to an anti-wear sintered alloy having excellent slidable property. More specifically, the invention relates to an anti-wear sintered alloy having improved self-lubricating property and fitness to an opponent sliding member of the anti-sintered alloy disclosed in U.S. Pat. No. 4,268,309 and in U.S. patent application Ser. No. 213,239. The invention also relate to a process for manufacturing such an anti-wear sintered alloy.
U.S. Pat. No. 4,268,309 discloses the anti-wear sintered alloy comprising 15 to 25 wt.% of Cr, 0.3 to 0.8 wt.% of P, 1 to 5 wt.% of Cu, 0 to 3 wt.% of Mo, 1.5 to 4.0 wt.% of C and the balance being Fe with less than 2 wt.% of impurities. (Hereinafter, "%" means "wt.%") U.S. patent application Ser. No. 213,239 discloses the anti-wear sintered alloy comprising 2.5-7.5% of Cr, 0.1-3.0% of Mn, 0.2-0.8% of P, 1-5% of Cu, 0-3% of Mo, 1.5-3.5% of C and the balance being Fe with less than 2% of impurities. These references describe that such anti-sintered alloys are suitable for use as a slidable member, such as a cam shaft and rocker arm in the valve operating system, which must be placed in service under high-plane pressure conditions because the sintered alloys in these references have an excellent anti-wear property with a high density and high hardness.
Under the circumstances that the high-performance of the automobiles has been strongly demanded in recent years, however, the service conditions of the rocker arm and cam are getting severer and severer.